Chimeric protein

Abstract

The present invention provides a chimeric protein which comprises a multi-spanning transmembrane protein fused to a FAS endodomain, wherein the multi-spanning transmembrane protein binds an extracellular ligand, leading to activation of the FAS endodomain. The chimeric protein is useful as a suicide gene. The invention also provides a cell, such as a T cell comprising such a chimeric protein, which is useful in adoptive T cell immunotherapy approaches.

The invention claimed is: 
     
       1. A chimeric protein comprising a multi-spanning transmembrane protein fused to a FAS endodomain,
 wherein the multi-spanning transmembrane protein comprises CD20 truncated at the amino-terminus so that it lacks up to 41 amino acids from the CD20 amino-terminus, or at the carboxy-terminus so that it lacks up to 61 amino acids from the CD20 carboxy-terminus, and 
 wherein the multi-spanning transmembrane protein binds at least one extracellular ligand selected from Rituxumab, Ofatumumab or Veltuzumab, leading to activation of the FAS endodomain. 
 
     
     
       2. The chimeric protein according to  claim 1 , which comprises a FAS endodomain fused to the carboxy-terminus of a truncated version of CD20, lacking up to 41 amino acids from the CD20 amino-terminus. 
     
     
       3. The chimeric protein according to  claim 1 , wherein the FAS endodomain comprises the sequence shown in SEQ ID NO: 20. 
     
     
       4. The chimeric protein according to  claim 1 , wherein the FAS endodomain comprises the amino acid sequence of SEQ ID NO: 29. 
     
     
       5. A chimeric protein comprising a multi-spanning transmembrane protein that consists of the amino acid sequence of SEQ ID NO: 4, SEQ ID NO: 5, or SEQ ID NO: 6 fused to a FAS endodomain, wherein the multi-spanning transmembrane protein binds at least one extracellular ligand selected from Rituxumab, Ofatumumab or Veltuzumab, leading to activation of the FAS endodomain. 
     
     
       6. The chimeric protein according to  claim 5 , wherein the FAS endodomain comprises the sequence shown in SEQ ID NO: 20. 
     
     
       7. The chimeric protein according to  claim 5 , wherein the FAS endodomain comprises the amino acid sequence of SEQ ID NO: 29. 
     
     
       8. A chimeric protein comprising:
 a multi-spanning transmembrane protein fused to a FAS endodomain, 
 wherein the multi-spanning transmembrane protein comprises the amino acid sequence of SEQ ID NO: 3 truncated at the amino terminus so that it lacks up to 41 amino acids from the amino-terminus of SEQ ID NO: 3, or truncated at the carboxy-terminus so that it lacks up to 61 amino acids from the carboxy-terminus of SEQ ID NO: 3, and optionally has one or both of the following substitution mutations:
 (a) an amino acid substitution at position A170 of SEQ ID NO: 3; 
 (b) an amino acid substitution at position P172 of SEQ ID NO: 3; and 
 
 wherein the multi-spanning transmembrane protein binds at least one extracellular ligand selected from Rituxumab, Ofatumumab or Veltuzumab, leading to activation of the FAS endodomain. 
 
     
     
       9. The chimeric protein according to  claim 8  that comprises the mutation P172W, with position 172 defined with reference to the full length CD20 sequence shown as SEQ ID NO: 3. 
     
     
       10. The chimeric protein according to  claim 8 , wherein the FAS endodomain comprises the amino acid sequence of SEQ ID NO: 29. 
     
     
       11. The chimeric protein according to  claim 8 , wherein the FAS endodomain comprises the sequence shown in SEQ ID NO: 20. 
     
     
       12. An isolated cell which expresses the chimeric protein according to  claim 1 . 
     
     
       13. An isolated cell which expresses the chimeric protein according to  claim 5 . 
     
     
       14. An isolated cell which expresses the chimeric protein according to  claim 6 . 
     
     
       15. An isolated cell which expresses the chimeric protein according to  claim 3 . 
     
     
       16. An isolated cell which expresses the chimeric protein according to  claim 4 . 
     
     
       17. An isolated cell which expresses the chimeric protein according to  claim 7 . 
     
     
       18. An isolated cell which expresses the chimeric protein according to  claim 8 . 
     
     
       19. An isolated cell which expresses the chimeric protein according to  claim 9 . 
     
     
       20. An isolated cell which expresses the chimeric protein according to  claim 10 . 
     
     
       21. An isolated cell which expresses the chimeric protein according to  claim 11 .